PED (Precession Electron Diffraction)

Precession electron diffraction (PED) is a specialized method to collect electron diffraction patterns in a transmission electron microscope (TEM). By rotating (precessing) a tilted incident electron beam around the central axis of the microscope, a PED pattern is formed by integration over a collection of diffraction conditions. This produces a quasi-kinematical diffraction pattern that is more suitable as input into directmethods algorithms to determine the crystal structure of the sample.

Application:

• Determine crystal structures, to identify lattice parameters and symmetry, and ultimately to solve the atomic structure ab initio.
• Through connection with the microscope scanning system, to map the local orientation of the specimen to investigate crystal texture, rotation and strain at the nanometre scale.